Image display device and image display method

Abstract

The purpose of the present invention is to provide an image display device capable of displaying an image at a wide angle of view while minimizing crosstalk. An image display device ( 10 - 1 ) according to the present invention includes an image formation system ( 100 - 1 ) configured to form an image from light, a light guide system ( 300 - 1 ), an incident optical system ( 200 - 1 ) configured to cause a plurality of rays of light forming different angles of view of the image to impinge on the light guide system ( 300 - 1 ), and a light diffraction system ( 400 - 1 ) configured to diffract the plurality of rays of light guided by the light guide system ( 300 - 1 ) to cause the plurality of rays of light to impinge on an eyeball in different directions. The light diffraction system ( 400 - 1 ) has incident angle selectivity for at least one of incident angles at which the plurality of rays of light guided by the light guide system ( 300 - 1 ) impinges on the light diffraction system ( 400 - 1 ).

1 . An image display device comprising:
 light;   an image formation system configured to form an image from a light guide system;   an incident optical system configured to cause a plurality of rays of light forming different angles of view of the image to impinge on the light guide system; and   a light diffraction system configured to diffract the plurality of rays of light guided by the light guide system to cause the plurality of rays of light to impinge on an eyeball in different directions, wherein   the light diffraction system has incident angle selectivity for at least one of incident angles at which the plurality of rays of light guided by the light guide system impinges on the light diffraction system.   
     
     
         2 . The image display device according to  claim 1 , wherein at least two of the incident angles of the plurality of rays of light are different from each other. 
     
     
         3 . The image display device according to  claim 2 , wherein the light diffraction system includes a plurality of diffraction parts having incident angle selectivity for at least one of the at least two incident angles. 
     
     
         4 . The image display device according to  claim 3 , wherein at least two of the plurality of diffraction parts have incident angle selectivity for different incident angles of the at least two incident angles. 
     
     
         5 . The image display device according to  claim 3 , wherein at least two of the plurality of diffraction parts have incident angle selectivity for an identical incident angle of the at least two incident angles. 
     
     
         6 . The image display device according to  claim 3 , wherein
 the light guide system includes a light guide plate, and   at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles are at least two rays of light that have propagated while totally reflecting at mutually different total reflection angles in the light guide plate.   
     
     
         7 . The image display device according to  claim 6 , wherein the at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles are at least two rays of light that have caused to impinge on the light guide plate at mutually different incident angles by the incident optical system. 
     
     
         8 . The image display device according to  claim 7 , wherein the incident optical system converts the plurality of rays of light forming different angles of view of the image into approximately parallel rays of light and causes the plurality of rays of light to impinge on the light guide plate. 
     
     
         9 . The image display device according to  claim 6 , wherein each of the plurality of diffraction parts is provided at a position that coincides with a common multiple of a propagation distance in the light guide plate of a corresponding one of the at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles. 
     
     
         10 . The image display device according to  claim 9 , wherein the common multiple is a least common multiple. 
     
     
         11 . The image display device according to  claim 6 , wherein ½ of a total reflection cycle of a ray of light having a longest total reflection cycle of the at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles coincides with an integral multiple of a total reflection cycle of a ray of light other than the ray of light having the longest total reflection cycle of the at least two rays of light. 
     
     
         12 . The image display device according to  claim 6 , wherein each of the plurality of diffraction parts is provided at at least a position where a ray of light that impinges on the light diffraction system at a corresponding one of the incident angles impinges on a surface, adjacent to the eyeball, of the light guide plate or at at least a position where a ray of light that impinges on the light diffraction system at a corresponding one of the incident angles impinges on a surface, remote from the eyeball, of the light guide plate. 
     
     
         13 . The image display device according to  claim 1 , wherein the light diffraction system diffracts a part of each of the plurality of rays of light guided by the light guide system toward a plurality of different positions adjacent to the eyeball. 
     
     
         14 . The image display device according to  claim 3 , wherein the light diffraction system includes a diffraction part group including at least two of the diffraction parts that sequentially diffract different parts of each of at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles toward a plurality of different positions adjacent to the eyeball. 
     
     
         15 . The image display device according to  claim 3 , wherein
 the plurality of diffraction parts includes the diffraction part having at least two diffraction structures laminated in a thickness direction of the light guide plate, and   the at least two diffraction structures each have incident angle selectivity for the at least two incident angles.   
     
     
         16 . The image display device according to  claim 3 , wherein
 the plurality of diffraction parts includes the diffraction part in which at least two diffraction patterns are provided, and   the at least two diffraction patterns each have incident angle selectivity for the at least two incident angles.   
     
     
         17 . The image display device according to  claim 2 , wherein at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles are identical in wavelength to each other. 
     
     
         18 . The image display device according to  claim 1 , wherein the image formation system further includes a chromatic aberration correction diffraction part configured to correct chromatic aberration in the light diffraction system. 
     
     
         19 . The image display device according to  claim 6 , wherein the incident optical system includes a correction member configured to correct a difference in optical path length between the at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles, the optical path length being from a position of incidence on the light guide plate to a corresponding one of the diffraction parts. 
     
     
         20 . The image display device according to  claim 6 , further comprising an optical member provided on a side of the light guide plate opposite from a position where the plurality of rays of light impinges on the light guide plate relative to a position where the light diffraction system is provided, wherein
 of the at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles, a ray of light other than a ray of light having a longest optical path length from the position of incidence on the light guide plate to a corresponding one of the diffraction parts is diffracted by the corresponding one of the diffraction parts after an optical path is folded back by the optical member.   
     
     
         21 . The image display device according to  claim 20 , wherein the optical member is disposed at a position where the difference in optical path length between the at least two rays of light that each impinge on the light diffraction system at a corresponding one of the at least two incident angles is smaller. 
     
     
         22 . The image display device according to  claim 1 , wherein
 the image formation system includes:   a light source;   a light deflector configured to deflect a ray of light emitted from the light source;   an optical element disposed on an optical path between the light source and the light deflector; and   a drive unit capable of moving the optical element in an optical axis direction of the optical element.   
     
     
         23 . The image display device according to  claim 22 , further comprising:
 a line-of-sight detection system configured to detect a line-of-sight that is an orientation of the eyeball; and   a control system configured to control the drive unit on a basis of a detection result of the line-of-sight detection system and/or an image display position.   
     
     
         24 . The image display device according to  claim 22 , further comprising a control system configured to control the drive unit on a basis of an image display position. 
     
     
         25 . The image display device according to  claim 1 ,
 further comprising a drive system capable of changing a position and/or an orientation of the image formation system.   
     
     
         26 . The image display device according to  claim 25 , further comprising:
 a line-of-sight detection system configured to detect a line-of-sight that is an orientation of the eyeball; and   a control system configured to control the drive system on a basis of a detection result of the line-of-sight detection system and/or an image display position.   
     
     
         27 . The image display device according to  claim 25 , further comprising a control system configured to control the drive system on a basis of an image display position. 
     
     
         28 . The image display device according to  claim 7 , wherein
 the incident optical system includes:   a collimating lens configured to convert the plurality of rays of light forming different angles of view of the image into approximately parallel rays of light; and   a mirror configured to reflect the plurality of rays of light converted into approximately parallel rays of light by the collimating lens in different directions for each space region to cause the plurality of rays of light to impinge on the light guide plate at different incident angles.   
     
     
         29 . The image display device according to  claim 7 , wherein
 the incident optical system includes:   a mirror; and   an optical system configured to cause the plurality of rays of light forming different angles of view of the image to impinge on the mirror at different angles for each angle of view region, and   the mirror reflects the plurality of incident rays of light toward the light guide plate.   
     
     
         30 . An image display method comprising:
 forming an image from light;   causing a plurality of rays of light forming different angles of view of the image to impinge on a light guide system;   guiding, by the light guide system, the plurality of rays of light; and   causing the plurality of rays of light guided in the guiding to impinge on an eyeball in different directions by diffracting, by a light diffraction system, the plurality of rays of light, wherein   the light diffraction system has incident angle selectivity for at least one of incident angles at which the plurality of rays of light guided by the light guide system impinges on the light diffraction system.   
     
     
         31 . The image display method according to  claim 30 , wherein at least two of the incident angles of the plurality of rays of light are different from each other. 
     
     
         32 . The image display method according to  claim 31 , wherein
 the light diffraction system has incident angle selectivity for at least one incident angle of the at least two incident angles, and   in the causing the plurality of rays of light to impinge, a ray of light incident on the light diffraction system at the at least one incident angle of the plurality of rays of light is selectively diffracted by the light diffraction system.